Compositional Phase Separation in La2-xBaxCuOy, near the Optimum Composition for Superconductivity

Kazuyoshi Yoshimura; Hiroshi Kubota; Hiroshi Tanaka; Yumiko Date; Makoto Nakanishi; Tomohiko Ohmura; Nobuhiro Saga; Takashige Sawamura; Takashi Uemura; Koji Kosuge

doi:10.1143/JPSJ.62.1114

Compositional Phase Separation in La2-xBaxCuOy, near the Optimum Composition for Superconductivity

Kazuyoshi Yoshimura, Hiroshi Kubota, Hiroshi Tanaka, Yumiko Date, Makoto Nakanishi, Tomohiko Ohmura, Nobuhiro Saga, Takashige Sawamura, Takashi Uemura, Koji Kosuge

Research output: Contribution to journal › Article › peer-review

12 Citations (Scopus)

Abstract

Compositional phase separation was observed in La2-xBaxCuOy near the optimum composition (a:-0.16) for superconductivity with a decisive miscibility gap by means of X-ray diffraction measurements. The phase-separated samples do not show intrinsic superconductivity. Therefore, the superconductive compound in this system is not in a chemical equilibrium state at low temperatures, but is a high-temperature phase obtained by quenching to room temperature. The critical temperature of the phase separation Tp takes a maximum value of 950°C at x~0.16, suggesting that phase instability is crucial for high-7; superconductors. The end composition of the miscibility gap in the Ba-poor composition region was found to be 0.12, which is a singular point from crystallographic and band structural standpoints.

Original language	English
Pages (from-to)	1114-1117
Number of pages	4
Journal	journal of the physical society of japan
Volume	62
Issue number	4
DOIs	https://doi.org/10.1143/JPSJ.62.1114
Publication status	Published - 1993
Externally published	Yes

Keywords

La2-xBaxCuO4
high-Tc superconductivity
phase separation

ASJC Scopus subject areas

Physics and Astronomy(all)

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10.1143/JPSJ.62.1114

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title = "Compositional Phase Separation in La2-xBaxCuOy, near the Optimum Composition for Superconductivity",

abstract = "Compositional phase separation was observed in La2-xBaxCuOy near the optimum composition (a:-0.16) for superconductivity with a decisive miscibility gap by means of X-ray diffraction measurements. The phase-separated samples do not show intrinsic superconductivity. Therefore, the superconductive compound in this system is not in a chemical equilibrium state at low temperatures, but is a high-temperature phase obtained by quenching to room temperature. The critical temperature of the phase separation Tp takes a maximum value of 950°C at x~0.16, suggesting that phase instability is crucial for high-7; superconductors. The end composition of the miscibility gap in the Ba-poor composition region was found to be 0.12, which is a singular point from crystallographic and band structural standpoints.",

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year = "1993",

doi = "10.1143/JPSJ.62.1114",

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T1 - Compositional Phase Separation in La2-xBaxCuOy, near the Optimum Composition for Superconductivity

AU - Yoshimura, Kazuyoshi

AU - Kubota, Hiroshi

AU - Tanaka, Hiroshi

AU - Date, Yumiko

AU - Nakanishi, Makoto

AU - Ohmura, Tomohiko

AU - Saga, Nobuhiro

AU - Sawamura, Takashige

AU - Uemura, Takashi

AU - Kosuge, Koji

PY - 1993

Y1 - 1993

N2 - Compositional phase separation was observed in La2-xBaxCuOy near the optimum composition (a:-0.16) for superconductivity with a decisive miscibility gap by means of X-ray diffraction measurements. The phase-separated samples do not show intrinsic superconductivity. Therefore, the superconductive compound in this system is not in a chemical equilibrium state at low temperatures, but is a high-temperature phase obtained by quenching to room temperature. The critical temperature of the phase separation Tp takes a maximum value of 950°C at x~0.16, suggesting that phase instability is crucial for high-7; superconductors. The end composition of the miscibility gap in the Ba-poor composition region was found to be 0.12, which is a singular point from crystallographic and band structural standpoints.

AB - Compositional phase separation was observed in La2-xBaxCuOy near the optimum composition (a:-0.16) for superconductivity with a decisive miscibility gap by means of X-ray diffraction measurements. The phase-separated samples do not show intrinsic superconductivity. Therefore, the superconductive compound in this system is not in a chemical equilibrium state at low temperatures, but is a high-temperature phase obtained by quenching to room temperature. The critical temperature of the phase separation Tp takes a maximum value of 950°C at x~0.16, suggesting that phase instability is crucial for high-7; superconductors. The end composition of the miscibility gap in the Ba-poor composition region was found to be 0.12, which is a singular point from crystallographic and band structural standpoints.

KW - La2-xBaxCuO4

KW - high-Tc superconductivity

KW - phase separation

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Compositional Phase Separation in La2-xBaxCuOy, near the Optimum Composition for Superconductivity

Abstract

Keywords

ASJC Scopus subject areas

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